1. Field of the Invention
The present invention relates to an endoscope apparatus having an autofocus function.
2. Description of the Related Art
In recent years, an endoscope including an image pickup unit employing a solid-state image pickup device has been widely used in a medical field.
There has also been proposed an endoscope including an optical system having an autofocus function to enable detailed observation of a diseased part and the like and an image pickup unit employing a solid-state image pickup device increased in the number of pixels.
For example, a conventional example of Japanese Patent Application Laid-Open Publication No. 2002-253489 discloses an endoscope apparatus that moves a part of lenses in an objective optical system to perform autofocus.
In the conventional example, when magnification controlling means is started up by operation of switching means, focus adjustment of the objective optical system is performed on a long focal length side in a variable focal length range of the objective optical system by focus controlling means started up in association with a control signal of the magnification controlling means.
In an examination or an observation by an endoscope, usually, a screening test is performed in a state in which the endoscope is focused on a far point side and, when a suspicious region is examined or observed in detail, operation for focusing the endoscope on a near point side is performed.